MODIFIED BROADBAND SCHIFFMAN PHASE SHIFTER USING DENTATE MICROSTRIP AND PATTERNED GROUND PLANE

Abstract—In this letter, a modified broadband 90 ◦ phase shifter is proposed. By using a dentate microstrip and a patterned ground plane, an extremely tight coupling can be obtained, and consequently a constant phase shift over a wide bandwidth can be achieved. To verify the proposed idea, a topology is implemented, the measured results of a phase difference of 90 ± 5 ◦ in 79.5 % bandwidth, better than 10 dB return loss across the whole operating band, are also given. The measurement results agree well with the full-wave electromagnetic simulated responses. 1